You should allow the secondary air to enter hot into the combustion. I am not sure the way you're planning the secondary air set up, will allow it to warm up enough.

JeffJetisoned

Posts : 80Join date : 2014-03-23

Subject: Re: Ice Hut Rocket Heater Thu Jul 31, 2014 1:49 pm

Last weekend I was at a local fest and they had nitrogen ice cream...don't ask me..never heard of it but there were about six or seven empty tanks sitting in alley and they all had Mississippi Welding written on the side of them. They were also stainless steel and looked to be high grade. I've seen compressed oxygen tanks that size but never nitrogen..guess I didn't know they had them but I would love to find some of these tanks at junk price or below to use for rocket stoves. Helium tanks are a great idea though and I have never thought to use them.

Tryin2hard used this method on his latest rocket stove cooker. So I will give it a try.Also cooler air has more O2 per unit volume than hot air so maybe it will work ok.

JeffJetisoned:These helium tanks are only mild steel and darn thin but they were free, for a light duty stove hopefully they will last a while . Darn though I really like stainless. It always fun searching the junk yards ...who knows what you will find. Just scored a 120 CFH gas cylinder for 30 bucks.It's now been re hydro tested and is now full of Argon.

Hitchhiker

Posts : 246Join date : 2013-12-26Location : nomad

Subject: Re: Ice Hut Rocket Heater Thu Jul 31, 2014 8:22 pm

Billhere wrote:

Caotropheus:

Also cooler air has more O2 per unit volume than hot air so maybe it will work ok.

First, I am not saying cool air will or will not work. Cooler air should take energy away from the gases, slow down any draft, and lower temps.

In tryinghard's test he got increased temps. The amount of cooling or thermal shock may be offset by the increased heat produced by combustion increase i.e. When one adds O2 to a cutting torch temps definitely increase. Now I realize air is only @ 21% O2 but still. The concentration per unit volume of cooler air could be double that of hot air. Another factor is the flow rate of air intake .So worst case scenario is I do not use the secondary if temps are reduced. There are so many variables running these stoves it is hard to do a real test. The quantity of fuel, the size of the fuel (surface area) etc. etc. I should have fun testing this out. In any case I appreciate your points.Will keep you posted

I think you hit the nail square on the head when you said it is hard to test these rocket stoves and know the results unless there is constant variables, which there hardly ever is..but, I sure appreciate educated best guesses and results based on one's hard work. Thanks again for sharing.

T2HAdmin

Posts : 908Join date : 2013-10-07

Subject: Re: Ice Hut Rocket Heater Tue Aug 05, 2014 3:18 pm

Hey bill really interesting take on your observations.I have found setting my harbor freight 220 volt wire welder at its lowest settings and setting it at a number 3 feed rate I can get a pretty good weld on very thin steel.

You really have to watch your speed advancement rate.

Had to laugh it was begging to be used! Love it!

Looking forward to your results, also I think Caotropheus is right on his observations concerning your secondary air placement, it looks a bit high above the combustion area, however...........what looks like is not always the case, so let us know ok.